Process for treating surface of plywood

ABSTRACT

ARCHITECTURAL FINISH IS IMPARTED TO SURFACE OF PLYWOOD BY ABRADING SURFACE WITH RAPIDLY MOVING ABRASIVE GRITCARRYING FLEXIBLE BELT.

Oct. 12, 1971 D. C. DAVIS PROCESS FOR TREATING SURFACE OF PLYWOOD Filed Aug. 25, 1969 DAVID C. DAVIS //Vl EN70/-? BUG/(HORN, BLORE, KLAROU/ST B SPAR/(MAN 47 T 0/?NE Y5 3,611,647 PROCESS FOR TREATING SURFAEE OE PLYWDOD David C. Davis, Aberdeen, Wash, assignor to Evans Products Company, Portland, Oreg. Filed Aug. 25, 1969, Ser. No. 852,618 Int. Q1. B241] 1/00 US. Cl. 511-328 1 Claim ABSTRACT OF THE DISCLOSURE Architectural finish is imparted to surface of plywood by abrading surface with rapidly moving abrasive gritcarrying flexible belt.

BACKGROUND OF THE INVENTION An architecturally pleasing surface has been imparted to the surface of plywood by subjecting the panel to the abrading action of tools so as to form the appearance of a resawn surface on the plywood. Such surface is characterized by alternating ridges and channels which gives highlights and shadows that are of a pleasing nature in appearance.

SUMMARY OF THE INVENTION DRAWINGS FIG. 1 is a schematic elevation of apparatus for performing the method of the invention;

FIG. 2 is a plan view of the apparatus shown in FIG. 1;

FIG. 3 is a plan view of a panel produced in accordance with the invention; and,

FIG. 4 is an enlarged section taken along line 4-4 of FIG. 3.

DESCRIPTION OF PREFERRED EMBODIMENT Referring to the drawings, the apparatus for carrying out the method of the invention includes a belt sander apparatus including a conveyor 10 for supporting a piece of plywood 12 in its approach to the position where the sanding operation will take place, and an off-bearing conveyor 14. Hold-down rolls 16 are also provided. A sanding belt 18 is trained over a drum 20 positioned so that the grit on the belt 18 engages the bottom surfaces of the panel 12 as it is carried over the drum on the conveyors 10, 14. The belt 18 is driven by a roll 22 powered from a suitable motor 24 through a belt 26.

a? angst? Patented Oct. 12, 1971 illtw tutti" In the conventional sanding apparatus utilized in the manufacture of plywood, the drum 20 which supports the abrasive belt engaging the surface of the plywood is oscillated in a direction parallel to its axis of rotation. In contrast, in apparatus for performing the process of the invention, it is important that the drum 20 be not oscillated but instead be fixed so as to have no movement in the direction parallel to its axis.

The grit on the belt 18 should have a coarseness at; least as great as No. 12 grit, and preferably greater, such as No. 16, and the grit should be relatively widely spaced apart, that is, at random intervals of from one-quarter to one inch apart. t t

In accordance with the method of the invention, a panel 12 is positioned on the conveyor 10 with the grain on the surface of the panel extending parallel to the axis of the drum 211. The panel 12 is then advanced in a direction perpendicular to its grain and perpendicular to the axis of the drum Z0 whereupon the grit on the belt 18 will remove material in the form of grooves and scratches '30 of irregular depth to impart an architecturally desirable surface to the panel.

In a typical process the panel is preferably advanced at a rate of about 28 feet per minute while the belt is driven with a drum speed of about 1200 rpm. with a drum diameter of 11% inches. The surface is free of slivers and, therefore, is easily handled without injury to the handler and may also be easily painted or stained. Because of the uncomplicated nature of the equipment upon which the method may be performed, the panels may be handled by relatively unskilled operators in the course of performing the process of the invention.

Having illustrated and described a preferred embodiment of my invention, it is apparent that it permits of modification and arrangement in detail.

I claim:

1. The method of producing an architectural finish upon the surface of a sheet of plywood which comprises moving a sheet of plywood horizontally in a direction at right angles to its grain while abrading said surface with a rapidly moving flexible belt carrying abrasive grit trained over a roll having its axis of rotation extending at right angles to the said direction of movement of said sheet, said grit being of a coarseness at least as great as No. 12 grit and being relatively widely spaced apart.

References Cited UNITED STATES PATENTS 1,932,092 10/1933 Hijo 51-137 2,706,873 4/1955 Gifford 51-137 2,762,173 9/1956 Bottcher 51l38 X 3,125,461 3/1964 Hofimann 51281 X 3,277,937 10/1966 Miles 144--115 LESTER M. SWINGLE, Primary Examiner US. Cl. X.R. 5l139; 144-115 

